Worker sync utility (#1511)

* patched an issue with wasmoon randomly asking to resolve proxy references
  * simplified pyodide and micropython dance by grouping their common utilities together
  * created an integration test around a worker to main thread input between MicroPython and Lua
  * commented some weird bugs / funny behaviors around both MicroPython and Pyodide
  * other minor clean ups

.pre-commit-config.yaml

@@ -14,7 +14,7 @@ repos:
           - id: check-docstring-first
           - id: check-executables-have-shebangs
           - id: check-json
-            exclude: tsconfig.json
+            exclude: tsconfig.json pyscript.core/cjs/package.json
           - id: check-toml
           - id: check-xml
           - id: check-yaml

.prettierignore

@@ -7,4 +7,5 @@ pyscript.core/micropython/
 pyscript.core/pyscript/
 pyscript.core/types/
 pyscript.core/esm/worker/xworker.js
+pyscript.core/cjs/package.json
 pyscript.core/min.js

pyscript.core/cjs/package.json

@@ -0,0 +1 @@
+{"type":"commonjs"}

pyscript.core/esm/loader.js

@@ -13,10 +13,11 @@ export const getRuntime = (id, config) => {
     if (config) {
         // REQUIRES INTEGRATION TEST
         /* c8 ignore start */
-        if (config.endsWith(".json")) options = fetch(config).then(getJSON);
+        if (config.endsWith(".json")) {
-        else if (config.endsWith(".toml"))
+            options = fetch(config).then(getJSON);
+        } else if (config.endsWith(".toml")) {
             options = fetch(config).then(getText).then(parse);
-        else {
+        } else {
             try {
                 options = JSON.parse(config);
             } catch (_) {

pyscript.core/esm/runtime/_python.js

@@ -0,0 +1,27 @@
+import { clean, writeFile as writeFileUtil } from "./_utils.js";
+
+// REQUIRES INTEGRATION TEST
+/* c8 ignore start */
+export const run = (runtime, code) => runtime.runPython(clean(code));
+
+export const runAsync = (runtime, code) => runtime.runPythonAsync(clean(code));
+
+export function runEvent(runtime, code, key) {
+    code = `import js;event=js.__events.get(${key});${code}`;
+    return this.run(runtime, code);
+}
+
+const worker = (method) =>
+    function (runtime, code, xworker) {
+        code = `from js import xworker;${code}`;
+        globalThis.xworker = xworker;
+        return this[method](runtime, code);
+    };
+
+export const runWorker = worker("run");
+
+export const runWorkerAsync = worker("runAsync");
+
+export const writeFile = ({ FS }, path, buffer) =>
+    writeFileUtil(FS, path, buffer);
+/* c8 ignore stop */

pyscript.core/esm/runtime/_utils.js

@@ -1,10 +1,26 @@
 import { getBuffer } from "../fetch-utils.js";
-import { absoluteURL } from "../utils.js";
+import { absoluteURL, defineProperty } from "../utils.js";
+import "@ungap/with-resolvers";
+
+// REQUIRES INTEGRATION TEST
+/* c8 ignore start */
+// TODO: this should *NOT* be needed as the polyfill
+//       already patches on demand the Promise object
+const { withResolvers } = Promise;
+defineProperty(globalThis, "Promise", {
+    configurable: true,
+    value: class extends Promise {
+        withResolvers() {
+            return withResolvers.call(this);
+        }
+    },
+});
+/* c8 ignore stop */
 
 /**
  * Trim code only if it's a single line that prettier or other tools might have modified.
  * @param {string} code code that might be a single line
- * @returns {strong}
+ * @returns {string}
  */
 export const clean = (code) =>
     code.replace(/^[^\r\n]+$/, (line) => line.trim());

pyscript.core/esm/runtime/micropython.js

@@ -1,15 +1,17 @@
-import { clean, fetchPaths, stdio, writeFile } from "./_utils.js";
+import { fetchPaths, stdio } from "./_utils.js";
+import {
+    run,
+    runAsync,
+    runEvent,
+    runWorker,
+    runWorkerAsync,
+    writeFile,
+} from "./_python.js";
 
 const type = "micropython";
 
 // REQUIRES INTEGRATION TEST
 /* c8 ignore start */
-const worker = (method) =>
-    function (runtime, code, xworker) {
-        globalThis.xworker = xworker;
-        return this[method](runtime, `from js import xworker;${code}`);
-    };
-
 export default {
     type: [type, "mpy"],
     module: () => `http://localhost:8080/micropython/micropython.mjs`,
@@ -20,16 +22,11 @@ export default {
         if (config.fetch) await fetchPaths(this, runtime, config.fetch);
         return runtime;
     },
-    run: (runtime, code) => runtime.runPython(clean(code)),
+    run,
-    runAsync: (runtime, code) => runtime.runPythonAsync(clean(code)),
+    runAsync,
-    runEvent(runtime, code, key) {
+    runEvent,
-        return this.run(
+    runWorker,
-            runtime,
+    runWorkerAsync,
-            `import js;event=js.__events.get(${key});${code}`,
+    writeFile,
-        );
-    },
-    runWorker: worker("run"),
-    runWorkerAsync: worker("runAsync"),
-    writeFile: ({ FS }, path, buffer) => writeFile(FS, path, buffer),
 };
 /* c8 ignore stop */

pyscript.core/esm/runtime/pyodide.js

@@ -1,15 +1,17 @@
-import { clean, fetchPaths, stdio, writeFile } from "./_utils.js";
+import { fetchPaths, stdio } from "./_utils.js";
+import {
+    run,
+    runAsync,
+    runEvent,
+    runWorker,
+    runWorkerAsync,
+    writeFile,
+} from "./_python.js";
 
 const type = "pyodide";
 
 // REQUIRES INTEGRATION TEST
 /* c8 ignore start */
-const worker = (method) =>
-    function (runtime, code, xworker) {
-        globalThis.xworker = xworker;
-        return this[method](runtime, `from js import xworker;${code}`);
-    };
-
 export default {
     type: [type, "py"],
     module: (version = "0.22.1") =>
@@ -26,16 +28,11 @@ export default {
         }
         return runtime;
     },
-    run: (runtime, code) => runtime.runPython(clean(code)),
+    run,
-    runAsync: (runtime, code) => runtime.runPythonAsync(clean(code)),
+    runAsync,
-    runEvent(runtime, code, key) {
+    runEvent,
-        return this.run(
+    runWorker,
-            runtime,
+    runWorkerAsync,
-            `import js;event=js.__events.get(${key});${code}`,
+    writeFile,
-        );
-    },
-    runWorker: worker("run"),
-    runWorkerAsync: worker("runAsync"),
-    writeFile: ({ FS }, path, buffer) => writeFile(FS, path, buffer),
 };
 /* c8 ignore stop */

pyscript.core/esm/toml.js

@@ -1,5 +1,5 @@
 // lazy TOML parser (fast-toml might be a better alternative)
-const TOML_LIB = `https://unpkg.com/basic-toml@0.3.1/es.js`;
+const TOML_LIB = `https://cdn.jsdelivr.net/npm/basic-toml@0.3.1/es.js`;
 
 /**
  * @param {string} text TOML text to parse

pyscript.core/esm/utils.js

@@ -1,6 +1,6 @@
 const { isArray } = Array;
 
-const { assign, create, defineProperty } = Object;
+const { assign, create, defineProperties, defineProperty } = Object;
 
 const { all, resolve } = new Proxy(Promise, {
     get: ($, name) => $[name].bind($),
@@ -8,4 +8,13 @@ const { all, resolve } = new Proxy(Promise, {
 
 const absoluteURL = (path, base = location.href) => new URL(path, base).href;
 
-export { isArray, assign, create, defineProperty, all, resolve, absoluteURL };
+export {
+    isArray,
+    assign,
+    create,
+    defineProperties,
+    defineProperty,
+    all,
+    resolve,
+    absoluteURL,
+};

pyscript.core/esm/worker/_template.js

@@ -4,6 +4,8 @@
 //    Please check via `npm run size` that worker code is not much
 //    bigger than it used to be before any changes is applied to this file.
 
+import coincident from "coincident/structured";
+
 import { registry } from "../runtimes.js";
 import { getRuntime, getRuntimeID } from "../loader.js";
 
@@ -20,7 +22,11 @@ const add = (type, fn) => {
         !!fn && { once: true },
     );
 };
+
 const xworker = {
+    // allows synchronous utilities between this worker and the main thread
+    sync: coincident(self),
+    // standard worker related events / features
     onerror() {},
     onmessage() {},
     onmessageerror() {},
@@ -35,16 +41,14 @@ const xworker = {
         return event;
     },
 };
+
 add("message", ({ data: { options, code } }) => {
     engine = (async () => {
         const { type, version, config, async: isAsync } = options;
         const engine = await getRuntime(getRuntimeID(type, version), config);
         const details = registry.get(type);
-        (run = details[`runWorker${isAsync ? "Async" : ""}`].bind(details))(
+        run = details[`runWorker${isAsync ? "Async" : ""}`].bind(details);
-            engine,
+        run(engine, code, xworker);
-            code,
-            (globalThis.xworker = xworker),
-        );
         return engine;
     })();
     add("error");

pyscript.core/esm/worker/class.js

@@ -1,5 +1,6 @@
+import coincident from "coincident/structured";
 import xworker from "./xworker.js";
-import { assign, defineProperty, absoluteURL } from "../utils.js";
+import { assign, defineProperties, absoluteURL } from "../utils.js";
 import { getText } from "../fetch-utils.js";
 
 /**
@@ -28,8 +29,15 @@ export default (...args) =>
         const bootstrap = fetch(url)
             .then(getText)
             .then((code) => postMessage.call(worker, { options, code }));
-        return defineProperty(worker, "postMessage", {
+        return defineProperties(worker, {
-            value: (data, ...rest) =>
+            postMessage: {
-                bootstrap.then(() => postMessage.call(worker, data, ...rest)),
+                value: (data, ...rest) =>
+                    bootstrap.then(() =>
+                        postMessage.call(worker, data, ...rest),
+                    ),
+            },
+            sync: {
+                value: coincident(worker),
+            },
         });
     };

pyscript.core/node.importmap

@@ -3,6 +3,6 @@
         "http://pyodide": "./test/mocked/pyodide.mjs",
         "https://cdn.jsdelivr.net/pyodide/v0.22.1/full/pyodide.mjs": "./test/mocked/pyodide.mjs",
         "http://localhost:8080/micropython/micropython.mjs": "./test/mocked/micropython.mjs",
-        "https://unpkg.com/basic-toml@0.3.1/es.js": "./test/mocked/toml.mjs"
+        "https://cdn.jsdelivr.net/npm/basic-toml@0.3.1/es.js": "./test/mocked/toml.mjs"
     }
 }

pyscript.core/package-lock.json

@@ -9,7 +9,9 @@
             "version": "0.0.0",
             "license": "ISC",
             "dependencies": {
-                "basic-devtools": "^0.1.6"
+                "@ungap/with-resolvers": "^0.1.0",
+                "basic-devtools": "^0.1.6",
+                "coincident": "^0.2.3"
             },
             "devDependencies": {
                 "@node-loader/import-maps": "^1.1.0",
@@ -19,8 +21,8 @@
                 "c8": "^7.14.0",
                 "eslint": "^8.42.0",
                 "linkedom": "^0.14.26",
-                "rollup": "^3.23.1",
+                "rollup": "^3.24.0",
-                "static-handler": "^0.4.0",
+                "static-handler": "^0.4.1",
                 "typescript": "^5.1.3"
             }
         },
@@ -335,6 +337,16 @@
             "integrity": "sha512-60BCwRFOZCQhDncwQdxxeOEEkbc5dIMccYLwbxsS4TUNeVECQ/pBJ0j09mrHOl/JJvpRPGwO9SvE4nR2Nb/a4Q==",
             "dev": true
         },
+        "node_modules/@ungap/structured-clone": {
+            "version": "1.2.0",
+            "resolved": "https://registry.npmjs.org/@ungap/structured-clone/-/structured-clone-1.2.0.tgz",
+            "integrity": "sha512-zuVdFrMJiuCDQUMCzQaD6KL28MjnqqN8XnAqiEq9PNm/hCPTSGfrXCOfwj1ow4LFb/tNymJPwsNbVePc1xFqrQ=="
+        },
+        "node_modules/@ungap/with-resolvers": {
+            "version": "0.1.0",
+            "resolved": "https://registry.npmjs.org/@ungap/with-resolvers/-/with-resolvers-0.1.0.tgz",
+            "integrity": "sha512-g7f0IkJdPW2xhY7H4iE72DAsIyfuwEFc6JWc2tYFwKDMWWAF699vGjrM348cwQuOXgHpe1gWFe+Eiyjx/ewvvw=="
+        },
         "node_modules/acorn": {
             "version": "8.8.2",
             "resolved": "https://registry.npmjs.org/acorn/-/acorn-8.8.2.tgz",
@@ -521,6 +533,14 @@
                 "wrap-ansi": "^7.0.0"
             }
         },
+        "node_modules/coincident": {
+            "version": "0.2.3",
+            "resolved": "https://registry.npmjs.org/coincident/-/coincident-0.2.3.tgz",
+            "integrity": "sha512-zCHSEa8x6HcXTaPQLH89//mu7UQn/Iie2xcSOhTMPu546lboT7Js2vr1HIlZHISe82++0y7JSnX/7gIWy0bcrw==",
+            "dependencies": {
+                "@ungap/structured-clone": "^1.2.0"
+            }
+        },
         "node_modules/color-convert": {
             "version": "2.0.1",
             "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-2.0.1.tgz",
@@ -1647,9 +1667,9 @@
             }
         },
         "node_modules/rollup": {
-            "version": "3.23.1",
+            "version": "3.24.0",
-            "resolved": "https://registry.npmjs.org/rollup/-/rollup-3.23.1.tgz",
+            "resolved": "https://registry.npmjs.org/rollup/-/rollup-3.24.0.tgz",
-            "integrity": "sha512-ybRdFVHOoljGEFILHLd2g/qateqUdjE6YS41WXq4p3C/WwD3xtWxV4FYWETA1u9TeXQc5K8L8zHE5d/scOvrOQ==",
+            "integrity": "sha512-OgraHOIg2YpHQTjl0/ymWfFNBEyPucB7lmhXrQUh38qNOegxLapSPFs9sNr0qKR75awW41D93XafoR2QfhBdUQ==",
             "dev": true,
             "bin": {
                 "rollup": "dist/bin/rollup"
@@ -1776,9 +1796,9 @@
             }
         },
         "node_modules/static-handler": {
-            "version": "0.4.0",
+            "version": "0.4.1",
-            "resolved": "https://registry.npmjs.org/static-handler/-/static-handler-0.4.0.tgz",
+            "resolved": "https://registry.npmjs.org/static-handler/-/static-handler-0.4.1.tgz",
-            "integrity": "sha512-ixtyrMNaN6Z0jW4RDJWL9BJT2kZ4wX05+D1XNGOOXxeUqrpk4MhZtMXdqQGxitRSrDCO6/Esjdq28rrvzDeYEw==",
+            "integrity": "sha512-atl+UofbqCECS4Ag1ZZIjC606I1I40CuDsdq4YQ5Vq3vTsUbvqVaNG4evFsKktlnPcEm217vBUSEFKyi9lsJ8Q==",
             "dev": true,
             "dependencies": {
                 "mime-types": "^2.1.34"
@@ -2275,6 +2295,16 @@
             "integrity": "sha512-60BCwRFOZCQhDncwQdxxeOEEkbc5dIMccYLwbxsS4TUNeVECQ/pBJ0j09mrHOl/JJvpRPGwO9SvE4nR2Nb/a4Q==",
             "dev": true
         },
+        "@ungap/structured-clone": {
+            "version": "1.2.0",
+            "resolved": "https://registry.npmjs.org/@ungap/structured-clone/-/structured-clone-1.2.0.tgz",
+            "integrity": "sha512-zuVdFrMJiuCDQUMCzQaD6KL28MjnqqN8XnAqiEq9PNm/hCPTSGfrXCOfwj1ow4LFb/tNymJPwsNbVePc1xFqrQ=="
+        },
+        "@ungap/with-resolvers": {
+            "version": "0.1.0",
+            "resolved": "https://registry.npmjs.org/@ungap/with-resolvers/-/with-resolvers-0.1.0.tgz",
+            "integrity": "sha512-g7f0IkJdPW2xhY7H4iE72DAsIyfuwEFc6JWc2tYFwKDMWWAF699vGjrM348cwQuOXgHpe1gWFe+Eiyjx/ewvvw=="
+        },
         "acorn": {
             "version": "8.8.2",
             "resolved": "https://registry.npmjs.org/acorn/-/acorn-8.8.2.tgz",
@@ -2416,6 +2446,14 @@
                 "wrap-ansi": "^7.0.0"
             }
         },
+        "coincident": {
+            "version": "0.2.3",
+            "resolved": "https://registry.npmjs.org/coincident/-/coincident-0.2.3.tgz",
+            "integrity": "sha512-zCHSEa8x6HcXTaPQLH89//mu7UQn/Iie2xcSOhTMPu546lboT7Js2vr1HIlZHISe82++0y7JSnX/7gIWy0bcrw==",
+            "requires": {
+                "@ungap/structured-clone": "^1.2.0"
+            }
+        },
         "color-convert": {
             "version": "2.0.1",
             "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-2.0.1.tgz",
@@ -3243,9 +3281,9 @@
             }
         },
         "rollup": {
-            "version": "3.23.1",
+            "version": "3.24.0",
-            "resolved": "https://registry.npmjs.org/rollup/-/rollup-3.23.1.tgz",
+            "resolved": "https://registry.npmjs.org/rollup/-/rollup-3.24.0.tgz",
-            "integrity": "sha512-ybRdFVHOoljGEFILHLd2g/qateqUdjE6YS41WXq4p3C/WwD3xtWxV4FYWETA1u9TeXQc5K8L8zHE5d/scOvrOQ==",
+            "integrity": "sha512-OgraHOIg2YpHQTjl0/ymWfFNBEyPucB7lmhXrQUh38qNOegxLapSPFs9sNr0qKR75awW41D93XafoR2QfhBdUQ==",
             "dev": true,
             "requires": {
                 "fsevents": "~2.3.2"
@@ -3325,9 +3363,9 @@
             }
         },
         "static-handler": {
-            "version": "0.4.0",
+            "version": "0.4.1",
-            "resolved": "https://registry.npmjs.org/static-handler/-/static-handler-0.4.0.tgz",
+            "resolved": "https://registry.npmjs.org/static-handler/-/static-handler-0.4.1.tgz",
-            "integrity": "sha512-ixtyrMNaN6Z0jW4RDJWL9BJT2kZ4wX05+D1XNGOOXxeUqrpk4MhZtMXdqQGxitRSrDCO6/Esjdq28rrvzDeYEw==",
+            "integrity": "sha512-atl+UofbqCECS4Ag1ZZIjC606I1I40CuDsdq4YQ5Vq3vTsUbvqVaNG4evFsKktlnPcEm217vBUSEFKyi9lsJ8Q==",
             "dev": true,
             "requires": {
                 "mime-types": "^2.1.34"

pyscript.core/package.json

@@ -5,7 +5,7 @@
     "main": "./cjs/index.js",
     "types": "./types/index.d.ts",
     "scripts": {
-        "server": "npx static-handler --cors --coep --coop .",
+        "server": "npx static-handler --cors --coep --coop --corp .",
         "build": "npm run rollup:xworker && npm run rollup:min && eslint esm/ && npm run ts && npm run cjs && npm run test",
         "cjs": "ascjs --no-default esm cjs",
         "rollup:min": "rollup --config rollup/min.config.js",
@@ -29,8 +29,8 @@
         "c8": "^7.14.0",
         "eslint": "^8.42.0",
         "linkedom": "^0.14.26",
-        "rollup": "^3.23.1",
+        "rollup": "^3.24.0",
-        "static-handler": "^0.4.0",
+        "static-handler": "^0.4.1",
         "typescript": "^5.1.3"
     },
     "module": "./esm/index.js",
@@ -45,9 +45,11 @@
     },
     "unpkg": "min.js",
     "dependencies": {
-        "basic-devtools": "^0.1.6"
+        "@ungap/with-resolvers": "^0.1.0",
+        "basic-devtools": "^0.1.6",
+        "coincident": "^0.2.3"
     },
     "worker": {
-        "blob": "sha256-kYwW0+fdul6LFbjoFeqku+pa9ARFxRtfmeM6zF53zLo="
+        "blob": "sha256-T0DDfoQde+3gciIoHqPGP2SgMQpbY/nAMjfd1cg8jyA="
     }
 }

pyscript.core/rollup/min.config.js

@@ -10,7 +10,7 @@ createRequire(import.meta.url)("./build_xworker.cjs");
 
 export default {
     input: "./esm/index.js",
-    plugins: [nodeResolve(), terser()],
+    plugins: process.env.NO_MIN ? [nodeResolve()] : [nodeResolve(), terser()],
     output: {
         esModule: true,
         file: "./min.js",

pyscript.core/rollup/xworker.config.js

@@ -16,7 +16,7 @@ const WORKERS_DIR = resolve(
 
 export default {
     input: join(WORKERS_DIR, "_template.js"),
-    plugins: [nodeResolve(), terser()],
+    plugins: process.env.NO_MIN ? [nodeResolve()] : [nodeResolve(), terser()],
     output: {
         esModule: true,
         file: join(WORKERS_DIR, "__template.js"),

pyscript.core/test/order.html

@@ -8,7 +8,9 @@
         <script type="importmap">
             {
                 "imports": {
-                    "basic-devtools": "../node_modules/basic-devtools/esm/index.js"
+                    "basic-devtools": "../node_modules/basic-devtools/esm/index.js",
+                    "coincident/structured": "../node_modules/coincident/structured.js",
+                    "@ungap/with-resolvers": "../node_modules/@ungap/with-resolvers/index.js"
                 }
             }
         </script>

pyscript.core/test/ruby.html

@@ -8,7 +8,9 @@
         <script type="importmap">
             {
                 "imports": {
-                    "basic-devtools": "../node_modules/basic-devtools/esm/index.js"
+                    "basic-devtools": "../node_modules/basic-devtools/esm/index.js",
+                    "coincident/structured": "../node_modules/coincident/structured.js",
+                    "@ungap/with-resolvers": "../node_modules/@ungap/with-resolvers/index.js"
                 }
             }
         </script>

pyscript.core/test/test.html

@@ -8,7 +8,9 @@
         <script type="importmap">
             {
                 "imports": {
-                    "basic-devtools": "../node_modules/basic-devtools/esm/index.js"
+                    "basic-devtools": "../node_modules/basic-devtools/esm/index.js",
+                    "coincident/structured": "../node_modules/coincident/structured.js",
+                    "@ungap/with-resolvers": "../node_modules/@ungap/with-resolvers/index.js"
                 }
             }
         </script>

pyscript.core/test/wasmoon.html

@@ -8,7 +8,9 @@
         <script type="importmap">
             {
                 "imports": {
-                    "basic-devtools": "../node_modules/basic-devtools/esm/index.js"
+                    "basic-devtools": "../node_modules/basic-devtools/esm/index.js",
+                    "coincident/structured": "../node_modules/coincident/structured.js",
+                    "@ungap/with-resolvers": "../node_modules/@ungap/with-resolvers/index.js"
                 }
             }
         </script>

pyscript.core/test/worker/index.html

@@ -8,6 +8,8 @@
             {
                 "imports": {
                     "basic-devtools": "../../node_modules/basic-devtools/esm/index.js",
+                    "coincident/structured": "../../node_modules/coincident/structured.js",
+                    "@ungap/with-resolvers": "../../node_modules/@ungap/with-resolvers/index.js",
                     "@pyscript/core": "../../esm/index.js"
                 }
             }

pyscript.core/test/worker/input.html

@@ -0,0 +1,73 @@
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8" />
+        <meta name="viewport" content="width=device-width,initial-scale=1.0" />
+        <title>python workers</title>
+        <script type="importmap">
+            {
+                "imports": {
+                    "basic-devtools": "../../node_modules/basic-devtools/esm/index.js",
+                    "coincident/structured": "../../node_modules/coincident/structured.js",
+                    "@ungap/with-resolvers": "../../node_modules/@ungap/with-resolvers/index.js",
+                    "@pyscript/core": "../../esm/index.js"
+                }
+            }
+        </script>
+        <script type="module">
+            import "@pyscript/core";
+        </script>
+    </head>
+    <body>
+        <script type="mpy">
+            from js import XWorker, Promise, document
+
+            deferred = Promise.withResolvers()
+
+            def handle_result(event):
+              inputs = document.querySelectorAll('input')
+              inputs[0].disabled = True
+              inputs[1].disabled = True
+              deferred.resolve(inputs[0].value)
+
+            def handle_input(data):
+              inputs = document.querySelectorAll('input')
+              inputs[0].placeholder = data
+              inputs[0].disabled = False
+              inputs[1].disabled = False
+              return deferred.promise
+
+            w = XWorker('./input.lua', type='lua')
+            w.sync.input = handle_input
+        </script>
+
+        <input type="text" placeholder="loading ..." required disabled />
+        <input type="submit" mpy-click="handle_result(event)" disabled />
+
+        <!--script type="mpy">
+          from js import XWorker, Array, Promise, Reflect, document
+
+          resolve = None
+
+          def trap_resolve(res, rej):
+            global resolve
+            resolve = res
+
+          def handle_result(event):
+            input = document.querySelector('input[type="text"]')
+            resolve(input.value)
+
+          def handle_input(data):
+            input = document.querySelector('input[type="text"]')
+            input.placeholder = data
+            input.disabled = False
+            # TODO: Promise.new(trap_resolve) does not work in MicroPython
+            #       but the following throws in Pyodide 😅 so fallback to deferred
+            return Reflect.construct(Promise, Array(trap_resolve))
+
+          # TODO: Proxy do not work in MicroPython so type='py' it is
+          w = XWorker('./input.py', type='py')
+          w.sync.input = handle_input
+      </script-->
+    </body>
+</html>

pyscript.core/test/worker/input.lua

@@ -0,0 +1,2 @@
+print('What is 2 + 3?')
+print('Answer: ' .. xworker.sync.input('What is 2 + 3?'))

pyscript.core/test/worker/input.py

@@ -0,0 +1,4 @@
+from js import xworker
+
+print("What is 2 + 3?")
+print("Answer: " + xworker.sync.input("What is 2 + 3?"))

pyscript.core/test/worker/input.rb

@@ -0,0 +1,6 @@
+require "js"
+
+xworker = JS::eval("return xworker")
+
+puts "What is 2 + 3?"
+puts xworker.sync.input("What is 2 + 3?")